Terpene ether



Patented Jan. 19, 1943 1 TERPENE ETHER Jacob M. Schantz, Wilmington,DeL, assignor to Hercules Powder Company, Wilmington, Del, a corporationof Delaware No Drawing. Application July 27, 1949,

Serial No. 348,021

12 Claims. (Cl. 260-611) This invention relates to the preparation ofterpene ethers and more particularly to the preparation of glycol andother polyhydric alcohol terpene ethers.

In Humphrey U. S, Patent No. 2,136,011, there is disclosed theproduction of a terpene ether containing one or more unreacted hydroxylgroups in the aliphatic radical, such as the reaction product ob'tainedby the addition of ethylene glycol to a double bond of an unsaturatedterpene compound such as alpha-pinene. However, such a product containsa large proportion of the diterpene ether of glycol wherein two terpenehydrocarbon radicals are attached one at each end of the dimethylene(-CH2.CH2) radical.

It is an object of the present invention to devise a method for thepreparation of an ether of a terpene radical and a hydroxyl substitutedorganic radical.

Another object is to provide for the direct preparation of such anether.

Another object is to prevent or, to a large extent, minimize theformation of di-terpene ethers whereby the resulting ether has itshydroxyl group free or unetherified. Numerous other objects of thepresent invention will more fully hereinafter appear.

I have discovered that an ether of a radical of a terpene compound and ahydroxyl substituted aliphatic hydrocarbon radical may be readilyprepared by treating an ether of a radical of a terpene compound and ahalogen substituted organic radical with an aqueous material such as anaqueous solution or mixture of an alkaline agent such as an alkali metalhydroxide, an al-,

kali metal carbonate, an alkali metal bicarbonate, an appreciablyWater-soluble alkaline earth metal hydroxide, etc. In this way, thedirect preparation of the monoterpene ethers is facilitated and theformation of the di-terpene ethers is prevented. Thus, a higher yield ofthe desired monoterpene ethers is obtained and the.

product is more suited to those uses which depend upon the content ofmono-terpene ethers. In addition, the higher yield of the desiredproduct produced in accordance with the present invention is veryadvantageous and results in less waste of raw material than previousprocesses.

As the starting material, I may use any ether of a terpene compound anda halogen substituted organic radical. However, I prefer to use an etherof a radical of a terpene hydrocarbon and a beta halogen substitutedaliphatic organic radical such as terpinyl beta-chloroethyl ether.Terpinyl beta-chloroethyl ether may be made for example in the mannerdescribed in the copending application of Donald H. Sheflield, SerialNo. 301,761, filed October 28, 1939, now U. 5. Patent No. 2,251,214 byreacting alpha pinene with ethylene chlorohydrin as follows: 400 g. ofalpha pinene were added to 600 g. of ethylene chlorohydrin and 12 g. of75% sulfuric acid and the mixture well agitated. The reaction which tookplace evolved heat; the temperature was maintained at 45 C. by cooling.After three hours the reaction was complete. Acid and excess ethylenechlorohydrin were then removed by two washes of about 500 g. each of 10%aqueous sodium carbonate solution. The result ing oil was thenfractionated into two components by distillation. One fraction consistedof terpene hydrocarbons. The other fraction consisted essentially ofterpinyl beta-chloro-' ethyl ether.

Instead of terpinyl beta-chloroethyl ether I may employ as the startingmaterial other ethers of a terpene radical and a beta-substituted orlandrene, sylvestrene, alpha terpineol, beta terpineol, or any of thep-menthenols, or other unsaturated monocyclic terpene alcohol, ormixtures thereof, any unsaturated complex cyclic terpene capable ofisomerization to an unsaturated monocyclic terpene compound such as,alpha pinene, carene, etc., or other unsaturated polycyclic terpene suchas nopin-ene, bornylene,

; alpha fenchene, sabinene, sabinol, thujene, borneol, isoborneol,fenchyl alcohol, etc. The terpene radical may be saturated such asp-menthyl, etc. or unsaturated.

I prefer to use the terpene ethers of beta-halo, 3 substituted aliphaticradicals such as ethyl,

stituted ethyl group because of the commercial.

availability of ethylene chlorohydrin. Thus the the preferred groupcomprises the terpene ethers of glycerin monochlorohydrin (either thealpha or the beta form), of glycerin dichlorohydrin (either the alpha orthe beta form), 2-chloro-' propyl terpene ethers (prepared by reactingthe terpene with 2-chloropropanol-1), Z-chloro-lmethyl-ethyl terpeneethers or beta-chloroism. propyl ethers (prepared by reacting theterpenewith 1-chloropropanol-2), terpene ethers made from but-ylenechlorohydrins such as beta-chlorobutyl terpene ethers (made by reactingthe terpene with 2-chlor-o-l-hydroxy-butane), J2--,chloro-l-methyl-propyl terpene ethers (made. by.

reacting the terpene with 3-chloro-2-hydroxybutane), 2 chloro 2 methylpropyl terpene ethers (made by reacting the terpene with 2-chloro-2-methyl propanol), beta-chloroamyl terpene ethers prepared byreacting terpenes with amylene chlorohydrins, and higher ethers. It ispreferred to use those terpene ethers which are made by reacting theunsaturated terpenewith a chlorohydrin in which the chlorine and thealcohol group are on adjacent carbon atoms due to the ease with whichsuch chlorohydrins are prepared from the readily available olefines. Useof such chlorohydrins results in the production of ethers in which thechlorine substitution is on the second carbon from the carbon joined tothe ether oxygen atom.

While it is preferred to use beta-halo-substituted ethers otherhalo-substituted ethers may be used provided that the halogensubstitution is on a carbon atom removed by at least one carbon atomfrom the ether oxygen atom. The use of halo-substituted ethers in whichthe halogen substitution is on a carbon atom more than twice removedfrom the ether oxygen atom is in general not feasible because suchethers are difficult to prepare and the halohydrins in which the OH andhalogen groups are on non-adjacent carbon atoms are not commerciallyavailable or easily prepared.

While it is preferred to employ ethers in which the organic radical, inwhich the halogen substitution is made, is an aliphatic radicalcontaining at least two carbon atoms such as ethyl, propyl, butyl, amyl,hexyl, heptyl, octyl, lauryl, pentadecyl, etc, other radicals may beemployed though less preferably, such as alicyclic radicals such ascyclohexyl, etc., aryl radicals such as phenyl, etc. However in view ofthe difficulty of preparing terpene ethers of such halo-substitutedradicals, their use is not preferred.

Where chlorine substitution is referred to, bromine o iodine may beemployed. However in view of the fact that iodohydrins cannot bedirectly or conveniently prepared, the iodine substituted ethers are notfeasible for use as a starting material. Instead of a singlesubstitution of a halogen on the alkyl group, two halogen atoms may besubstituted on the same or on difierent carbon atoms of the alkyl groupof the ether.

The invention may be carried out by admixing the terpene ether of thehalogen substituted organic radical with an aqueous solution orsuspension of an alkali of suitable type, followed by agitation of themixture so as to cause intimate contact of the reacting components andsubjection of the mixture to an elevated temperature for a prolongedperiod of time. After the reaction has taken place to the desiredextent, the terpene ether of the hydroxyl substituted organic radicalmay be recovered in any desired manner and may be purified if desired.The purification may, for example, be carried out by distillation underreduced pressure.

It is preferred to employ an aqueous solution of an alkali to bringabout the reaction. Examples of alkaline materials which have been foundsuitable are the alkali metal hydroxides, such as, sodium, potassium andlitmum hydroxide, the alkali metal carbonates such as, sodium andlithium carbonate, the alkali metal bicarbonates such as sodium andpotassium bicarbonate, and the alkaline earth metal hydroxides, namely,calcium hydroxide, barium hydroxide and strontium hydroxide. Of thesematerials, the alkali metal hydroxides are preferred because of theireffectiveness, and of the alkali metal hydroxides sodium hydroxide ispreferred on account of its cheapness. The stronger alkaline materialssuch as sodium and potassium hydroxide are also more suitable in thecase of a primary halogen group. Where the raw material contains asecondary halogen group, somewhat weaker alkalies such as the alkalimetal carbonates, alkali metal bicarbonates or alkaline earth metalhydroxides may be employed. In many cases, tertiary halogen reacts stillmore readily than the secondary halogen, and water alone will oftenbring about the desired conversion of an ether containing a tertiaryhalogen group to a hydroxyl substituted terpene ether although anaqueous alkali is preferred because of increased speed. From theforegoing, it will be seen that weaker alkalies such as the alkalineearth metal hydroxides, the alkali metal carbonates, very dilute sodiumor potassium hydroxide or water alone may be employed to bring about thedesired reaction.

In addition to the effect of the position of the halogen group on theradical, and the effect imparted by whether it is primary, secondary, ortertiary, the nature of the halogen in the halogen group controls theease with which the reaction takes place. A bromine group reacts lessreadily than an iodine group and a chlorine group reacts still lessreadily than a bromine group.

The concentration of the aqueous alkaline material may vary within widelimits, depending upon the difiiculty with which the reaction isefected, for example from 0% up to about 60 or and preferably from about1% to about 50%. In the case of a primary group, such as is present interpinyl beta chloroethyl ether, this concentration can range from about5% to about 40%, and preferably between about 10% and about 30%.

The amount of alkaline material employed may range from about 1.1 toabout 10 mols of alkali per mol of terpene chloro ether taken, in thecase of a primary chlorine group. The preferable range is from about 1.5to about 3 mols of alkali per mol of chloro ether. These mol ratioswould be doubled in the case where the terpene contained two etherlinked halogen substituted hydrocarbon radicals.

The temperature employed in carrying out the reaction may vary withinwide limits depending upon the reactivity of the particular raw materialtaken, the concentration of the aqueous alkali, the amount of alkaliemployed based on the weight of the raw material, etc. In general, thetemperature will range between about and about 300 C. and preferablybetween about and 200 C. in the case of the primary halogen substitutedterpene ethers. Lower temperatures, say from room temperature to about200 C. are suitable in the case of tertiary halogen substituted ethers.In the case of secondary substituted ethers, temperatures ranging from50 to 250 C. may be employed. The temperature will also vary with thereactivity of the particular alkali employed. Thus, for example, in thecase of primary chlorides, the reaction with the alkali metal carbonatesand the alkaline earth metal hydroxides is much slower than with thealkali metal hydroxides so that with the former alkalies, highertemperatures are necessary than with the latter.

If desired, the process may be carried out under pressure in a suitablepressure-resisting vessel, The pressure employed may vary fromatmospheric up to 100 atmospheres. However, since ordinarily thereaction takes place with satisfactory speed at atmospheric pressure,the use of such high pressures is generally not necessary. Where,however, the reaction does not proceed with the desired speed, it may beaccelerated by the employment of elevated pressures.

If desired, solvents may be present in thereaction mixture, Where thereactants or the product is viscous or in order to speed up thereaction. Inert solvents, such as, benzene, toluene, xylene,cyclohexane, petroleum hydrocarbon solvents, such as, V. M. & P.naphtha, gasoline, Stoddard solvent, dipentene, hydrogenated petroleumnaphtha, etc. may be employed. Mutual solvents for all the reactants maybe used. Solvents which are not inert may be employed. Thus, theutilization of aqueous ethyl alcohol reduces materially the yield ofby-product resinous material, since it is a mutual solvent for the rawmaterial, sodium hydroxide, water, and,

the product. By the use of a mutual solvent, the difficulty occasionedby the low solubility of the raw material in the aqueous media whichcauses the reaction to proceed less rapidly than desirable, may beovercome.

Below are given several specific examples showing methods of carryingout the present invention.

Example 1 50 g. (0.23 mol) of terpinyl beta-chloroethyl ether made byreacting alpha pinene with ethylene chlorohydrin in the presence ofsulfuric acid in the manner described above, were admixed with asolution of 25 g. (0.625 mol) of sodium hydroxide in 150 g. of water.The mixture was placed in a shaking autoclave, heated to 180 C., andmaintained at this temperature with continual agitation for 24 hours.Pressure developed during the treatment. Following the treatment, themixture was allowed to undergo layer formation whereupon the oily layerwas separated and distilled at 2 millimeters pressure. The distillatebetween 90 and 105 C. was a colorless oil. This product contained 1.1%chlorine, 6.2% OH as determined by acetylation, 8.9% OH as determined bythe Zerewithofi method, and was estimated to contain about 80% of glycolmonoterpinyl ether. The yield of glycol monoterpinyl ether was 70%.

The product before distillation was dark in color and contained 0.9%chlorine. The residue left upon distillation amounted to about 25% ofthe product before distillation and comprised a viscous dark-coloredresin containing 0.2% chlorine.

Examples 2 to 6 Additional examples are indicated in the following tablein which 50 g. lot of terpinyl betachloroethyl ether were reacted as inExample 1 to give glycol monoterpinyl ether, the conditions of reactionbeing as indicated in the table:

50 g. of terpinyl beta-chloroethyl ether was added to a solution of 25g. of sodium hydroxide, 70 g. of ethyl alcohol and'BO g. of water. Themixture was agitated 24 hours at 180 C. in a bomb. After washing theoily layer with water and distilling it under reduced pressure asinExample 1, a 5% resinous residue remained and the distillate containedno chlorine and appeared to be mainly glycol monoterpinyl ether withasmall amount of glycol ethyl terpinyl ether. Apparently, conditions weresuch that the ethyl radical was substituted to a slight degree for thehydrogen of the hydroxyl of the glycol monoterpinyl ether, or that theethoxy radical was substituted in part for the chlorine group of the rawmaterial. The use of aqueous ethyl alcohol as the solvent greatlyreduced the yield of resinous by-products and is not dis-advantageousfor many uses because for many purposes a mixture of glycol monoterpinylether and glycol ethyl terpinyl ether is satisfactory.

From the foregoing, it will be seen that the present invention makespossible the ready production of glycol monoterpinyl ether and relatedcompounds without any etherification by the terpene radical of thesecond hydroxyl group in the aliphatic chain. Numerous other advantagesof the process of the present invention will be apparent to thoseskilled in the art.

It will be understood that the details and examples hereinbefore setforth are illustrative only and that the invention as broadly describedand claimed is in no way limited thereby.

' What I claim and desire to protect by Letters Patent is:

1. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted aliphaticalcohol to form an ether of a radical of a terpene compound and ahalogen substituted organic radical, and reacting the ether thus formedwith an aqueous alkaline medium to form said ether of a radical of aterpene compound and a hydroxyl substituted organic radical.

2. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted aliphaticalcohol to form an ether of a radical of a terpene compound and ahalogen substituted organic terpene radical, and reacting the ether soformed with an agent selected from the group consisting of water andaqueous alkaline media to form said ether of a radical of a terpenecompound and a hydroxyl substituted organic radical.

3. A process of preparing glycol monoterpinyl ether which comprisesreacting alpha-pinene with ethylene chlorohydrin to form a terpinylbeta-chloroethyl ether, and reacting the ether thus formed with anaqueous alkaline medium to form the glycol monoterpinyl ether.

4. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted organic alcoholto form an ether of a radical of a terpene compound and a halogensubstituted organic radical, and reacting the ether thus formed with anaqueous alkaline medium to form said ether of a radical of a terpenecompound and a hydroxyl substituted organic radical.

5. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting adicyclic unsaturated terpene compound with a halogenv substitutedorganic alcohol to form an ether of a radical of a terpene compound anda halogen substituted organic radical, and reacting the ether thusformed with an aqueous alkaline medium.

6. A process of preparing glycol monoterpinyl ether which comprisesreacting dipentene with ethylene chlorohydrin to form a terpinylbetachloroethyl ether, and reacting the ether thus formed with anaqueous alkaline medium to form the glycol monoterpinyl ether.

7. A process of preparing glycol monoterpinyl ether which comprisesreacting terpinolene with ethylene chlorohydrin to form a terpinylbetachloroethyl ether, and reacting the ether thus formed with anaqueous alkaline medium to form the glycol monoterpinyl ether.

8. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted organic alcoholto form an ether of a radical of a terpene compound and a halogensubstituted organic radical, and reacting the ether thus formed withwater containing an alkaline agent selected from the group consisting ofthe alkaline metal hydroxides, carbonates and bicarbonates, and thealkaline earth metal hydroxides.

9. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted organic. alcoholto form an ether of a radical of a terpene compound and a halogensubstituted organic radical, and reacting the ether thus formed withwater containing an alkaline agent selected from the group consisting ofthe alkali metal hydroxides, carbonates and bicarbonates, and thealkaline earth metal hydroxides, the amount of said alkaline agentranging from about 1.1 to about mols per mol of said ether.

10. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted organicalcohohto form an ether of a radical of a terpene compound and a halogensubstituted organic radical, and reacting the ether thus formed withwater containing an alkaline. agent selected from the group consistingof the alkali, metal hydroxides, carbonates and bicarbonatcs, and thealkaline earth metal hydroxides, the amount of said alkaline agentranging from about 1.5 to about 3 mols per mol of ether, perether-linked halogen substituted organic radical in said ether.

11. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a halogen substituted organic alcoholto form an ether of a radical of a terpene compound and a halogensubstituted organic radical, and reacting the ether thus formed withwater containing an alkaline agent selected from the group consisting ofthe alkali metal hydroxides, carbonates and bicarbonates, and thealkaline earth metal hydroxides, said alkaline agent being employed inan amount ranging from about 1.5 to about 3 mols per ether-linkedhalogen substituted organic radical in said ether, the concentration ofsaid alkaline agent in the water of solution or mixture ranging fromabout 10 to about 30% by weight, at a temperature ranging from about C.to about 300 C. for a period of time sunicient to bring aboutsubstantial formation of said ether of a radical of a terpene compoundand a hydroxyl substituted organic radical.

12. A process of preparing an ether of a radical of a terpene compoundand a hydroxyl substituted organic radical which comprises reacting anunsaturated terpene compound with a betachloro substituted aliphaticstraight-chain alcohol' to form an ether of a radical of a terpenecompound for a beta-chloro substituted organic alco hol, and reactingthe ether thus formed with an aqueous alkaline medium.

JACOB M. SCHANTZ.

